Human respiratory illnesses are a burgeoning cause of morbidity for individuals who work in concentrated animal feeding operations (CAFO). Contact with high densities of livestock in close quarters exposes CAFO workers to large quantities of airborne microbes, antigens, and toxins, which combine to induce acute and chronic respiratory disorders. CAFO workers, particularly those working with swine and poultry, are at the forefront of risk for emerging zoonotic diseases of intense public health concern, including avian influenza, swine influenza, and multi-drug resistant pathogens. Except for the most acute infections, the etiological agents of lung disorders in CAFO workers are not well characterized, because most available microbiological knowledge has depended on culture, which is poorly informative. In contrast, molecular-based assays, such as broad-range polymerase chain reaction (PCR) can provide comprehensive surveys of microbial populations. Moreover, molecular assays can be performed much more rapidly and less expensively than can conventional culture-based techniques. The goals of the proposed four-year program are to use advanced molecular techniques to fully characterize the microbiology of bio-aerosols associated with selected CAFOs and to employ these techniques to test the efficacies of two engineering processes for bio-aerosol disinfection: U.V. irradiation and electrical discharge. Longitudinal air sampling will be performed at two each of swine, poultry, and cattle CAFOs in order to generalize results. The findings of this study are potentially critical for controlling CAFO workers'exposures to harmful microorganisms, advancing diagnostics, directing antimicrobial therapies, and measuring treatment outcomes. The specific objectives of this project are to: 1. Identify and quantify microorganisms associated with CAFO bio-aerosols using traditional and culture- independent technology. 2. Develop and validate PCR-based assays applicable to detection and quantification of bio-aerosol- associated microbes. 3. Evaluate U.V. irradiation and electrical discharge methods of bio-aerosol disinfection in controlled, laboratory environment. 4. Determine the impact on total and viable microbial loads in CAFOs following mitigation with U.V. irradiation and electrical discharge methods of bio-aerosol disinfection.